Act quickly if lightning strikes a tree in your yard
A lightning-struck tree brings to mind bright explosions and charred shells where a tree once stood. But what happens when lightning hits a tree? Trees experience lightning strikes in many different ways and can often survive with the right care. Let’s dive into the details of what a lightning strike does to a tree, and how many can survive.
Lightning occurs when pressure in thunderclouds creates a negative charge, a serious imbalance compared to the positive charge near the ground below. Nature seeks an equilibrium, and when lightning forms a connection, a powerful charge courses to the ground—creating a lightning bolt. It’s no surprise that this lightning pathway forms more easily in objects closer to the clouds, like tall buildings or trees.
That lightning strike can be immensely powerful, carrying down 100,000s of volts. Where the current passes through, materials can be heated up to 50,000 degrees Fahrenheit. Some trees can survive lightning strikes if the lightning damage is not severe. But the tree will be weakened and even mild lightning strikes can expose a tree to disease or pest attacks.
We’ll skip the rest of the science lesson, and go straight to the part about trees: Common reactions to this superheated current include:
The tree explodes: If lightning finds a path through the sapwood or greenwood of the tree, it will instantly ignite the sap and explosively turn the water into steam. Even the most durable tree species can’t survive that sudden expansion, and it may explode violently. Some estimates report that around half of the trees struck by lightning die immediately by explosion.
The outer damage runs the length of the tree: This result is common when lightning is channeled through the bark, burning a strip of the bark off on its way to the ground and causing some wood damage. Since the inner wood damage is relatively light, trees typically survive, but it creates an opening for bugs and tree fungi to reach vulnerable sapwood inside so the tree will be weaker.
The tree is split or partially destroyed: If lightning reaches more vulnerable inner wood, it causes considerably more damage, often splitting the tree in half or causing deep cracks. Survival is difficult but sometimes possible.
The tree burns: Even if lightning causes minimal damage, it can ignite leaves, branches, and nearby sap. The tree catches fire and will likely burn down or suffer significant damage. In a forest, the fire can quickly spread, which is why lightning is a common cause of natural forest fires.
Lightning will destroy the tree roots: Sometimes the easiest path lightning finds is tree roots. That’s bad news for the tree: Roots can be heavily damaged, the damage is hard to identify, and it can start underground fires. Trees can struggle to survive with significant root damage, so even if they suffer minor damage they can slowly die if their roots are burned severely.
What determines if a tree can survive lightning or what path a lightning strike takes? Some of Mother Nature’s effects are tough to predict, but important factors include:
Age: The more mature a tree, the larger it has grown, making it a more likely victim of lightning and increasing the damage lightning can do as it moves down the tree.
Moisture: In a rainstorm, lightning often takes a path through the water on a tree (water is far more conductive than woody trees), which can greatly reduce the damage to a tree.
Species: The type of tree, the thickness of its bark, how much moisture it holds in its wood, and other factors all affect the damage taken.
Multiple Strikes: Lightning strikes the same place twice all the time, and in a lengthy thunderstorm, it may strike a tall or isolated tree several times.
Keep these points in mind when caring for a tree that’s been struck by lightning:
Find out if the tree is healthy enough to survive. You’ll want to inspect the tree closely to see the extent of the damage, if there’s fire danger, and any exposure of the tree’s inner wood. You’ll also want to look for any damage running down the trunk close to the ground, which could indicate the roots are damaged, too.
If your inspection takes you into uncharted territory, you may want to contact a tree maintenance service near you that can offer a consultation. Professionals can offer valuable services like tree “bracing” to support a damaged tree while it tries to recover.
Remove the tree if the damage is too great. Tree removal costs an average of $750, depending on the tree’s type, health, and size.
Trees can heal from minor damage on their own, although they will be more vulnerable. You can help by ensuring the tree is disease-free and has plenty of water.
If there’s severe bark damage, you can use a knife or shears to carefully remove broken, burnt, or damaged bark.
Remove dead branches before they start decaying. It’s not usually necessary to coat damaged parts of the tree, but spraying with a “contact” fungicide or insecticide may help depending on the species, season, and local threats.
Add a tree-friendly fertilizer to encourage recovery. Again, local professionals can recommend the best kind of fertilizer to use for your soil.
Avoid any extensive pruning of healthy branches for at least one year.
You can build a lightning protection system to protect a more isolated tree on your property from regional thunderstorms. This process involves attaching lightning rods to the tree to catch the lightning and channel it down cables into the ground. That process depends on the shape of the tree and takes specialized work, so we highly recommend hiring a local tree service pro with experience in protecting trees from lightning.
Lightning can cause massive damage, fires, and openings for other threats like bugs or fungal diseases. Barring any large fires or explosions, it’s difficult to tell how much damage a lightning strike has done until after a thorough inspection. Contact local authorities immediately if lightning strikes a tree in your yard and it causes a fire or explosion.
Some tree species are more at risk for lightning strikes, particularly those that grow tall, need lots of room, or are planted in more isolated spots. Some examples include oak, pine, gum, poplar, and maple trees. On the other hand, lower and close-growing species are less likely to get hit, so birch and beech trees are rarely affected.
Stay inside or well away until the storm passes. Don’t go outside to inspect the tree until the weather clears, especially if the tree is on a hill or isolated in a field. Lightning often strikes the same easily-accessed places multiple times, and you could be a new target. If a lightning strike causes a noticeable fire, alert emergency services. When the storm is over, take a closer look to gauge the damage done.
After a big storm, you may not be sure if a tree was struck or not. Look for the telltale long scars, like strips or gouges in the bark of the tree, running in sometimes jagged lines down the length of the trunk. These scars will often show vulnerable living wood inside the tree. It’s also common to see scorched or wilted leaves on the side or top of the tree where lightning struck.
